Single metal programmability in a customizable integrated circuit device

ABSTRACT

A customizable integrated circuit including a substrate, a plurality of logic units formed on the substrate and a plurality of metal routing layers formed on the substrate for interconnecting the plurality of logic units. The plurality of metal routing layers includes a first routing layer including a plurality of elongate conductors extending generally in a given direction, a second routing layer including a plurality of transversely extending conductors, each adapted for interconnecting a termination of one of the plurality of elongate conductors to a beginning of another one of the plurality of elongate conductors and at least a third routing layer, including a plurality of local routing conductors, a plurality of customizable connections between pairs of the plurality of elongate conductors via individual ones of the plurality of transversely extending conductors and customizable connections between individual elongate conductors and a plurality of individual local routing conductors.

This is a continuation of application Ser. No. 09/707,726 filed Nov. 7,2000 now U.S. Pat. No. 6,459,136.

FIELD OF THE INVENTION

The present invention relates to integrated circuits generally and moreparticularly to customizable integrated circuits and methods ofcustomizing same.

BACKGROUND OF THE INVENTION

Various types of customizable integrated circuits are known in the art.The following U.S. patents are believed to represent the state of theart: U.S. Pat. Nos. 5,903,490; 5,742,181; 5,679,967; 5,260,597;5,049,969; 4,933,738; 4,960,729; 4,924,287; 4,240,094. Reference is alsomade to UK Patent 1135992 and to the various references appearing in theforegoing patents.

SUMMARY OF THE INVENTION

The present invention seeks to provide an improved customizableintegrated circuit and method for customizing same.

There is thus provided in accordance with a preferred embodiment of thepresent invention a customizable integrated circuit including:

a substrate;

a plurality of logic units formed on the substrate; and

a plurality of electrically conducting routing layers formed on thesubstrate for interconnecting the plurality of logic units, theplurality of electrically conducting routing layers including:

-   -   a first routing layer including a plurality of elongate        conductors extending generally in a given direction;    -   a second routing layer including a plurality of transversely        extending conductors, each adapted for interconnecting a        termination of one of the plurality of elongate conductors to a        beginning of another one of the plurality of elongate        conductors; and    -   at least a third routing layer including:        -   a plurality of local routing conductors;        -   a plurality of customizable connections between pairs of the            plurality of elongate conductors via individual ones of the            plurality of transversely extending conductors; and        -   customizable connections between individual ones of the            plurality of elongate conductors and a plurality of            individual ones of the local routing conductors.

There is also provided in accordance with a preferred embodiment of thepresent invention a customizable integrated circuit including:

a substrate;

a plurality of logic units formed on the substrate; and

a plurality of electrically conducting routing layers formed on thesubstrate for interconnecting the plurality of logic units, theplurality of electrically conducting routing layers including:

-   -   a first routing layer including a plurality of elongate        conductors extending generally in a given direction;    -   a second routing layer including a plurality of transversely        extending conductors, each adapted for interconnecting a        termination of one of the plurality of elongate conductors to a        beginning of another one of the plurality of elongate        conductors; and    -   at least a third routing layer including:        -   a plurality of customizable connections between pairs of the            plurality of elongate conductors via individual ones of the            plurality of transversely extending conductors, the            plurality of customizable connections being arranged            generally in at least one row.

The third routing layer may also include a plurality of customizableconnections between individual ones of the plurality of elongateconductors and one of a ground line and a power supply line, wherebyelongate conductors may serve as anti-crosstalk shields between adjacentother ones of the plurality of elongate conductors.

There is additionally provided in accordance with a preferred embodimentof the present invention a customizable integrated circuit including:

a substrate;

a plurality of logic units formed on the substrate; and

a plurality of electrically conducting routing layers formed on thesubstrate for interconnecting the plurality of logic units, theplurality of electrically conducting routing layers including:

-   -   a first routing layer including a plurality of elongate        conductors extending generally in a given direction;    -   a second routing layer including a plurality of transversely        extending conductors, each adapted for interconnecting a        termination of one of the plurality of elongate conductors to a        beginning of another one of the plurality of elongate        conductors; and    -   a third routing layer including:        -   a plurality of customizable connections between individual            ones of the plurality of elongate conductors and one of a            ground line and a power supply line, whereby elongate            conductors may serve as anti-crosstalk shields between            adjacent other ones of the plurality of elongate conductors.

The first, second and third routing layers may or may not lie inrespective sequential layers over the substrate.

The at least a third routing layer may include one or more routinglayers.

Preferably, the at least a third routing layer includes:

-   -   a plurality of local routing conductors; and    -   a plurality of customizable connections between pairs of the        plurality of elongate conductors via individual ones of the        plurality of transversely extending conductors.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully fromthe following detailed description, taken in conjunction with thedrawings in which:

FIG. 1 is a simplified three-dimensional illustration of part of thestructure of a customizable integrated circuit constructed and operativein accordance with a preferred embodiment of the present invention;

FIG. 2A is a simplified three-dimensional illustration of part of thestructure of FIG. 1 with the addition of additional parts of thestructure of a customizable integrated circuit constructed and operativein accordance with a preferred embodiment of the present invention;

FIG. 2B illustrates the structure of FIG. 2A, which is customized in oneof a plurality of possible configurations;

FIG. 3A illustrates the structure of FIG. 1 wherein elongate conductorsare connected to ground or to a power line;

FIG. 3B illustrates the structure of FIG. 2 wherein elongate conductorsare formed with customizable connections to ground or to a power line ata centralized location; and

FIG. 4 is a simplified two dimensional illustration of a third routinglayer showing possible customizable connections between variousconductors.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference is now made to FIG. 1, which is a simplified three-dimensionalillustration of a repeated part of the structure of a customizableintegrated circuit constructed and operative in accordance with apreferred embodiment of the present invention. As seen in FIG. 1, thereis provided a customizable integrated circuit comprising a substrate 10,typically a silicon substrate onto which are formed a plurality of logicunits (not shown).

A plurality of electrically conducting routing layers are formed on thesubstrate for interconnecting the plurality of logic units. Theplurality of electrically conducting routing layers includes a firstrouting layer 12 including a plurality of elongate conductors 14extending generally in a given orientation, indicated generally byarrows 16.

As seen in FIG. 1, the conductors 14 may be preferably arranged in amutually nested stepped orientation wherein each elongate conductor 14includes a plurality of short transverse portions 18, which interconnectelongated portions 20. Elongate portions 20 typically extend parallel toarrows 16, while transverse portions 18 extend perpendicularly to arrows16 in the same plane as elongate portions 18.

A second routing layer 22, which may be placed above or below firstrouting layer 12, includes a plurality of transversely extendingconductors 24, each adapted for interconnecting a termination of one ofsaid plurality of elongate conductors 14 to a beginning of another oneof said plurality of elongate conductors 14.

As seen in FIG. 1, each transversely extending conductor 24 is coupledat a first end thereof to an end of an elongate conductor 14 by a via 26and is coupled at a second end thereof to a via 28, which extends to athird routing layer 30. In accordance with a preferred embodiment of thepresent invention, adjacent each via 28 is a via 32, extending from thethird routing layer 30 to the first routing layer 12 and connecting toan end of an elongate conductor 14.

It is noted that the ends of vias 28 and 32 lie adjacent to each otherin the third routing layer 30 and define a customizable connectionbetween pairs of the plurality of elongate conductors 14 via individualones of the plurality of transversely extending conductors 24. It isalso noted that via pairs 28 and 32 are mutually spaced from each otheralong the directions indicated by arrows 16 typically by the length ofelongate portions 20 and are typically arranged in a row extendingparallel to the directions indicated by arrows 16.

Reference is now made to FIG. 2A, which is a simplifiedthree-dimensional illustration of part of the structure of FIG. 1,which, for convenience is designated using the same reference numeralsas used in FIG. 1, with the addition of additional parts of thestructure of a customizable integrated circuit constructed and operativein accordance with a preferred embodiment of the present invention.

As seen in FIG. 2A, the third routing layer 30 includes a plurality oflocal routing conductors 36 which typically extend generallyperpendicular to the directions indicated by arrows 16. In addition,there is provided a fourth routing layer 38 typically comprising aplurality of local routing conductors 40, which typically extendgenerally parallel to the directions indicated by arrows 16. Vias 42 mayextend from local routing conductors 40 to the third routing layer 30,which may lie above or below the fourth routing layer 38.

It is appreciated that the routing layers described in FIGS. 1 and 2Aare typically not the only routing layers provided in an integratedcircuit constructed and operative in accordance with an embodiment ofthe present invention. There are typically provided additional routinglayers which may or may not participate in the functionality describedherein.

Reference is now made to FIG. 2B, which illustrates the structure ofFIG. 2A, which is customized in one of a plurality of possibleconfigurations. The structure of FIG. 2B, which, for convenience isdesignated using the same reference numerals as used in FIGS. 1 and 2A,with the addition of additional parts of the structure of a customizableintegrated circuit constructed and operative in accordance with apreferred embodiment of the present invention.

In the illustrated embodiment of FIG. 2B, a plurality of customizableconnections, generally indicated by reference numeral 50, are providedbetween pairs of the plurality of elongate conductors 14 via individualones of the plurality of transversely extending conductors and aplurality of customizable connections, generally indicated by referencenumeral 52, are provided between individual ones of said plurality ofelongate conductors 14 and a plurality of individual ones of said localrouting conductors 36 and 40.

Additionally, a plurality of customizable connections, generallyindicated by reference numeral 54, are provided between individual onesof said plurality of the local routing conductors 40 and a plurality ofindividual ones of said local routing conductors 36.

An example of a customizable connection 50 is a connection 72, whichconnects vias 28 and 32, thus connecting an elongate conductor 14 bymeans of a transverse conductor 24 and via 28 with another conductor 14,by means of via 32.

An example of a customizable connection 52 is a connection 78, whichconnects vias 28 and 42, thus connecting an elongate conductor 14 bymeans of transverse conductor 24 and the via 28 with a local conductor40 by means of via 42.

Another example of the use of the customizable connection 52 is aconnection 74, which connects via 32 and the local routing conductor 36,thus connecting an elongate conductor 14 by means of via 32 and thelocal conductor 36.

An example of the use of the customizable connection 54 is a connection66, which connects the local routing conductor 40, by means of the via42, with the local routing conductor 36.

Reference is made in this connection additionally to FIG. 4, whichillustrates seven different connection possibilities, indicatedrespectively by reference numerals 70, 72, 74, 76, 78, 80 and 82. FIG.4, which, for convenience is designated using the same referencenumerals as used in FIGS. 1-2B, with the addition of additional parts ofthe structure of a customizable integrated circuit constructed andoperative in accordance with a preferred embodiment of the presentinvention.

Connection possibility 70 provides a customizable connection between anelongate conductor 14 by means of via 32 and a local conductor 40 of aneighboring part of the structure, by means of a via 42. Connectionpossibility 72 (also shown in FIG. 2B) provides a customizableconnection between an elongate conductor 14 by means of via 32 andanother elongate conductor 14 by means of a transverse conductor 24 anda via 28. Connection possibility 74 (also shown in FIG. 2B) provides acustomizable connection between an elongate conductor 14 by means of via32 and a local conductor 36. Connection possibility 76 provides acustomizable connection between an elongate conductor 14 by means of via32 and another local conductor 36.

Connection possibility 78 (also shown in FIG. 2B) provides acustomizable connection between an elongate conductor 14 by means of atransverse conductor 24 and a via 28 and a local conductor 40 by meansof a via 42. Connection possibility 80 provides a customizableconnection between an elongate conductor 14 by means of a transverseconductor 24 and a via 28 and the local conductor 36. Connectionpossibility 82 provides a customizable connection between an elongateconductor 14 by means of a transverse conductor 24 and a via 28 andanother local conductor 36.

Reference is now made to FIG. 3A, which illustrates the structure ofFIG. 1 wherein elongate conductors are connected to ground or to a powerline, collectively designated by reference numeral 90. It is appreciatedthat the connection of a given elongate conductor to ground or the powerline may be governed by the presence or absence of a connection betweenvias 28 and 32.

Reference is now made to FIG. 3B, which illustrates the structure ofFIG. 1 wherein elongate conductors 14 are formed with customizableconnections 94 to ground or to a power line 90 at a centralizedlocation, as distinguished from the embodiment of FIG. 3A, wherein theconnection of a given elongate conductor to ground or the power line maybe governed by the presence or absence of a connection between via pairs28 and 32, which are distributed along the length of the elongateconductors 14.

It will be appreciated by persons skilled in the art that the presentinvention is not limited by what has been particularly shown anddescribed hereinabove. Rather the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove as well as variations and modifications whichwould occur to persons skilled in the art upon reading the specificationand which are not in the prior art.

1. A customizable integrated circuit comprising: a substrate; aplurality of logic units formed on said substrate; and a plurality ofelectrically conducting routing layers formed on said substrate forinterconnecting said plurality of logic units, said plurality ofelectrically conducting routing layers including: a first routing layerincluding a plurality of elongate conductors extending generally in agiven direction; a second routing layer including a plurality oftransversely extending conductors, each adapted for interconnecting atermination of one of said plurality of elongate conductors to abeginning of another one of said plurality of elongate conductors; and athird routing layer including: a plurality of customizable connectionsbetween individual ones of said plurality of elongate conductors and oneof a ground line and a power supply line, whereby elongate conductorsmay serve as anti-crosstalk shields between adjacent other ones of saidplurality of elongate conductors.
 2. A customizable integrated circuitcomprising: a substrate; a plurality of logic units formed on saidsubstrate; and a plurality of electrically conducting routing layersformed on said substrate for interconnecting said plurality of logicunits, said plurality of electrically conducting routine layersincluding: a first routing layer including a plurality of elongateconductors extending generally in a given direction; a second routinglayer including a plurality of transversely extending conductors, eachadapted for interconnecting a termination of one of said plurality ofelongate conductors to a beginning of another one of said plurality ofelongate conductors; and at least a third routing layer including; aplurality of local routing conductors; a plurality of customizableconnections between pairs of said plurality of elongate conductors byway of individual ones of said plurality of transversely extendingconductors; customizable connections between individual ones of saidplurality of elongate conductors and a plurality of individual ones ofsaid local routine conductors; and a plurality of customizableconnections between individual ones of said plurality of elongateconductors and one of a ground line and a power supply line, wherebyelongate conductors may serve as anti-crosstalk shields between adjacentother ones of said plurality of elongate conductors.
 3. A customizableintegrated circuit comprising: a substrate; a plurality of logic unitsformed on said substrate; and a plurality of electrically conductingroutine layers formed on said substrate for interconnecting saidplurality of logic units, said plurality of electrically conductingrouting layers including: a first routine layer including a plurality ofelongate conductors extending generally in a given direction; a secondrouting layer including a plurality of transversely extendingconductors, each adapted for interconnecting a termination of one ofsaid plurality of elongate conductors to a beginning of another one ofsaid plurality of elongate conductors; and at least a third routinglayer including: a plurality of customizable connections between pairsof said plurality of elongate conductors by way of individual ones ofsaid plurality of transversely extending conductors, said plurality ofcustomizable connections being arranged generally in at least one row,and a plurality of customizable connections between individual ones ofsaid plurality of elongate conductors and one of a ground line and apower supply line, whereby elongate conductors may serve asanti-crosstalk shields between adjacent other ones of said plurality ofelongate conductors.
 4. A customizable integrated circuit comprising: asubstrate; a plurality of logic units formed on said substrate; and aplurality of electrically conducting routine layers formed on saidsubstrate for interconnecting said plurality of logic units, saidplurality of electrically conducting routine layers including: a firstroutine layer including a plurality of elongate conductors extendinggenerally in a given direction; a second routing layer including aplurality of transversely extending conductors, each adapted forinterconnecting a termination of one of said plurality of elongateconductors to a beginning of another one of said plurality of elongateconductors; and at least a third routing layer including: a plurality oflocal routine conductors; a plurality of customizable connectionsbetween pairs of said plurality of elongate conductors by way ofindividual ones of said plurality of transversely extending conductors;customizable connections between individual ones of said plurality ofelongate conductors and a plurality of individual ones of said localrouting conductors, and at least a third and a fourth routing layer. 5.A customizable integrated circuit comprising: a substrate; a pluralityof logic units formed on said substrate; and a plurality of electricallyconducting routing layers formed on said substrate for interconnectingsaid plurality of logic units, said plurality of electrically conductingroutine layers including: a first routine layer including a plurality ofelongate conductors extending generally in a given direction; a secondrouting layer including a plurality of transversely extendingconductors, each adapted for interconnecting a termination of one ofsaid plurality of elongate conductors to a beginning of another one ofsaid plurality of elongate conductors; and at least a third routinelayer including: a plurality of customizable connections between pairsof said plurality of elongate conductors by way of individual ones ofsaid plurality of transversely extending conductors, said plurality ofcustomizable connections being arranged generally in at least one row,and at least a third and a fourth routing layer.